Fire detection thermostat



Feb. 7, 1967 p. 1 KOOPMAN 3,303,308

FIRE DETECTION THERMOSTAT Filed Jan. 20, 1964 y @zo INVENTOR. P/l/P J. KOOP/WAN Mawr-1A M United States Patent O 3,393,308 FIRE DETECTHON THERMOSTAT Philip J. Koopman, New York, NX., assignor, by mesne assignments, to Gilbert Levy, Closter, NJ. Filed Ian. 20, 1964, Ser. No. 333,862 Claims. (Cl. 20d-142) This invention relates to a fire detection thermostat and is applicable to that type of thermostat that will actuate an alarm device when a predetermined temperature is -attained and also contains mechanism to -actuate the alarm device only after a predetermined rate of rise is produced.

The rate of rise control -is conventional in the art and consists of venting means which are of such size as to permit stabilization of the interior pressures unless a rate of rise greater than the allowable amount is produced. However, with this type of thermostat, it is also necessary to cause actuation of the alarm device when the temperature exceeds a predetermined amount regardless of the rate of rise and it is to this feature that the instant invention is directed.

In the thermostat of this invention the actuation of the -alarm device after a predetermined temperature is reached and regardless of the rate of rise by plugging the venting means so that the interior pressures become unbalanced and the switch means therewithin are actuated.

Various means are proposed in this speciiication to permit plugging of the vent means. The means set forth involve the general principle of placing stopper means which are normally spaced from the vent yinto the vent opening so as to close the same. One means illustrated involves the use of an actuator to which the stopper is sec-ured in normal spaced relationship to the vent opening Iand thence changing the shape of the actuator so that the stopper enters the vent opening.

The means proposed in this specification are simple and advantageous in operation, are relatively inexpensive and avoid failures.

The above constitutes a brief description of this invention and the advantages thereof.

The invention will now be further described .by reference to the accompanying drawings which are made a part of this specification.

FIG. 1 is a longitudinal sectional View of -a fire detection thermostat made in accordance with this invention.

FIG. 2 is a fragmentary bottom plan view, partly in section, ofthe thermostat sho'wn in FIG. 1.

FIG. 3 is a detail sectional view of one form of structure which can be used to place the stopper means within the vent opening when a predetermined temperature has been attained. In this ligure the spring, actuator, and associated structure have been removed for clarity of illustration of the remaining parts.

FIG. 4 is a detail fragmentary longitudinal sectional view of an alternative form of structure which can be used to place the stopper means within the vent opening when a predetermined temperature has been attained.

FIG. 5 is a top View, partly in section, of the type of actuator illustrated in FIG. 4.

FIG. 6 is a sectional view taken along lines 6-6 of FIG. 7.

FIG. 7 is a top view, on an enlarged scale, of the type of stopper and actuator illustrated in FIG. 4.

FIG. 8 is a diagrammatic view of the circuit which may be utilized to cause the switch means of the thermostat of this invention to actuate an alarm.

A detailed description of this invention will now be given by reference to the forms thereof set forth in the accompanying drawings whichrepresent the best modes known to the applicant for taking advantage of his inice vention. However, before commencing the detailed description, the reader is informed that the specific forms of the instant invention set forth therein are for illustrative purposes and for purposes of example only. Various changes and modifications may obviously Ibe made within the spirit and scope of this invention and would occur to those skilled in this art.

The thermostat 11 of this .invention is formed with a casing 12. A pair of cont-acts 13 and 14 constituting switch means are disposed therewithin. Contact 14 is electrically connected by conductive portion 15 to terminal 16 from which wire 17 extends. Contact 13 is electrically secured to spring 1S which in turn is secured to contact 19 which in turn bears wire 20. Screw 14 is threadedly secured within recess 21 and the t between screw 14 and recess '21 is a very loose one so that air m-ay pass therethrough. Screw 14 is secured in position by nut 22 which is also loosely fitted so that air may pass therethrough.

Openings 23 and 24 are provided to permit thermostat 11 to be secured in position upon a wall, a door, a lioor, or similar surface.

A vent 25 is located 'within the lower portion of thermostat 11. A filtering member 26, such as foamed plastic, is disposed within vent 25.

A channeled member 27 bearing tins 28 thereupon is disposed adjacent vent 25 and secured to portion 29 located at the lower surface of thermostat 11. Channeled portion 25 bears projections 30 which are disposed within mating recesses 31. Openings 32 are also provided so that channeled portion 2.5 can be twisted and locked into position.

Channeled portion 25 is also formed with a channel 33 and a cap 34. Cap 34 bears spring 35 secured thereto. Spring 35 may either be a compression spring or a tension spring and, in FIG. 1, spring 35 is a compression spring. One end portion 36 of spring 35 is secured to cap 34 while the opposite end portion 37 bears against the lateral surface of actuator 38 so as to force actuator 38 into the form shown in FIG. 1. Actuator 38 bears stopper 39 thereupon which is normally in spaced relati-onship from the lower portion 40 of vent 25. Cap 34 is secured within channel portion 25 by a metallic Iadhesive plug 41 which is made of a fusible low melting point metal such as Woods metal.

In the alternative structure shown in FIGS. 4, 5, 6 and 7 actuator 38a is formed of two dissimilar metals 43 and 44 which have differential rates of expansion and are secured to one another. Stopper 39a is secured in position upon actuator 38a. In the normal position actuator 38a is formed in arcuate shape as indicated and stopper 39a is spaced from the lower portion 40 of vent 25.

With the foregoing description the operation of this invention can now be explained. At the outset the structure shown in FIG. 1 and associated figures will now -be described.

When a predetermined temperature has been attained fusible metal 41 melts and releases cap 34 thereby releasing the compression of spring 35. As a result act-uator 38 which is deformed into U-shape by the pressure of spring 35 is released and forms a configuration shown by the dotted lines in FIG. l. This causes stopper 39 to enter portion 40 of vent 25 blocking this vent. As a result the gas 50 located in the lower portion of thermostat 1-1 expands and pushes contacts 13 and 14 together. The closing of these contacts causes an electrical circuit to flow from power means 51 and actuates alarm device 52. When the cause of the temperature rise has been eliminated the thermostat can be easily re-activated by simply replacing another channeled por-tion 25 with associated structure.

It is also obvious that spring 35 can be a tension spring in which case it would pull on the mid-portion of actuator 39.

The actuation of the alternative structure set forth in FIGS. 5 through 7 is similar except, that when a predetermined temperature has been attained, actuator 38a changes its shape to the shape shown by the dotted lines in FIG. 4. This causes stopper 39a to enter the lower portion 40 of vent 25 and cause similar actuation. However with this structure, when the tempera-ture reaches its normal value actuator 38a forms its normal shape as shown in FIGS. 4 and 6 causing unblock-ing of vent 2-'5 and the thermostat is ready for continued use without the necessity of replacing parts.

The foregoing description illustrates the manner in i which the objects of this invention are achieved.

cap and said actuator, said spring normally forcing said actuator into U-shape, wherein attainment of a predetermined temperatnre rise will release said spring and thus will cause said stopper to enter said vent and to close the same.

2. A thermostat for detecting a predetermined temperature rise comprising a hollow container having air there- Within, a normally open vent within said container, a channel adjacent said vent, a pair 1of normally open contacts within said container, said contacts being closeable by expansion of said air when said vent is closed, a stopper normally clear of and spaced from said vent, a normally U-shaped actuator secured to said stopper, a cap, a fusible metal link holding said cap, said link located within said channel, a deformed compres-sion spring intervening said cap and said actuator, said spring normally forcing said actuator into U-shape, wherein attainment of a predetermined temperature rise .will release said spring and thus will cause said stopper to enter said vent' and to close the same.

6. A thermostat .for Vdetecting a predetermined temperature rise comprising a hollow container having air therewithin, a normally 'open vent within said container, a channel adjacent said vent, a pair of normally open contacts within said -container,'said contacts being closeable by expansion of said air when said vent is closed, a

stopper normally clear of and spaced from said vent, a normally U-sh-aped. actuator secured to said stopper, a cap, a fusible metal link holding said capi, said link located within said channel, a deformed tension spring intervening said cap and said actuator, said spring normally forcing said actuator into U-shape, wherein attainment of a predetermined temperature rise will release said spring and thus will cause said stopper to enter said vent and to close the same.

4. A thermostat for detecting a predetermined temperature rise comprising a hollow container having -air therewithin, a normally open vent within said container, a channel adajcent said vent, cooling fins upon the outside of said channel, a pair of normally open contacts within said container, said contacts being closeable by expansion of said air` when said vent is cl-osed, a stopper normally clear of .and spaced from said vent, a normaily U- shaped actuator secured to said stopper, a cap, a fusible metal link holding said cap, said link located within said channel, a deformed tension spring intervening said cap yand said actuator, said spring normally forcing sai-d actuator into U-shape, wherein attainment of a predetermined temperature rise will release said spring and thus will canse said stopper to enter said vent and to close the same.

`5'. A thermostat for detecting a predetermined temperature rise comprising a hollow container'havin-g air therewithin, a normally open vent within said container, a channel adjacent said vent, a pair of normally open contacts within said container, said contacts being closeable by expansion of said air when said vent is closed, a stopper normally clear of and spaced from said vent, a normally U-shaped actuator secured to said stopper, said actuator formed of a pair of metals with differential rates of expansion overlying one another, wherein attainment of a predetermined temperature rise will detorm said actuator into substantially inverted U-shape `form and thus will cause said stopper to enter said vent and to close the same :and wherein a predetermined temperature drop from said level of temperature rise will cause said stopper to leave said vent and to open the same.

References Cited by the Examiner UNITED STATES PATENTS 2,029,097 l/ 1936 Garner 200-142 2,392,087 1/1946 Griffith 20G-140 X 2,413,140 12/1946 Griith ZOO-142 X 2,420,775 5/ 1947 Griffith 200--140 2,742,927 4/ 1956 Frumet 73-378.3 X

BERNARD A. GILHEANY, Primary Examiner.

B. GILSON, Assistant Examiner. 

1. A THERMOSTAT FOR DETECTING A PREDETERMINED TEMPERATURE RISE COMPRISING A HOLLOW CONTAINER HAVING AIR THEREWITHIN, A NORMALLY OPEN VENT WITHIN SAID CONTAINER, A CHANNEL ADJACENT SAID VENT, A PAIR OF NORMALLY OPEN CONTACTS WITHIN SAID CONTAINER, SAID CONTACTS BEING CLOSEABLE BY EXPANSION OF SAID AIR WHEN SAID VENT IS CLOSED, A STOPPER NORMALLY CLEAR OF AND SPACED FROM SAID VENT, A NORMALLY U-SHAPED ACTUATOR SECURED TO SAID STOPPER, A CAP, 